Aviation trainer



May 25, 1948. K. A. RAIL AVIATION TRAINER Filed July 5', 1943 3Sheets-Sheet 1 I KARL AKAIIL INVENTOR.

W ATTORNEYS May 25, 1948. KNL 2,442,205

AVIATION TRAINER Filed July 5, 1943 3 Sheets-Sheet 2 KARL AKAIL vINVENTOR.

I XVM May 25, 1948. L 2,442,205

AVIATION TRAINER Filed July 5, 1945 3 Sheets-Sheet 3 49 l I I 47 45 364O 38 I79 13s I35 I65 70 I54- 15s 2&

KARL 'AKAIL INVENTOR.

Patented May 25, 1948 2,442,205 AVIATION TRAINER Karl A. Kail, Montrose,Pa., assignor to Link Aviation, Inc., a corporation of New YorkApplication July 5, 1943, Serial No. 493,558

26 Claims.

The invention of this application which is a continuation in part of theabandoned application of Franklin A. Fish and myself, Serial Number448,906, filed June 29,1942, and of my copending application SerialNumber 452,739, filed July 29, 1942, relates to trainers for aviators,and comprises means for simulating in a grounded trainer the response ofan airplane and many of theinstruments thereof to certain conditions offlight.

My invention has been found to be particularly useful and will bedescribed in connection with an aviation trainer which constitutesessentially a simulated aircraft fuselage mounted upon a universal jointwhereby the trainer can be turned, pitched, and banked in all the usualflying positions of a real plane. Such a trainer is disclosed in U. S.P. 1,825,462. United States Patent 2,099,857 discloses means whereby thefunctioning of certain of the instruments in an airplane, such as thealtimeter, vertical speed indicator, and air speed indicator may besimulated in such a trainer.

One of the principal objects of this invention is to-provide, in such atrainer, means whereby the functioning of certain of the instruments ina plural motor aircraft may be simulated.

A more specific object of this invention is to provide means whereby theair speed and vertical speed indicators as well as the altimeter in thetrainer may be made to respond to a change in the setting of one or bothof the throttles in the trainer in a manner similar to the way thecorresponding instruments in a plural engine plane respond to a similarchange in the settings of one or both of the throttles in a plane.

A still further object of this invention is the provision of meanswhereby such a trainer may be made to rotate and bank when the throttlesettings therein are unequal, thereby simulating the turning and bankingof a dual engine plane caused by a difference in the speeds of theengines therein.

' A further object of my invention is the provision of means wherebywhen such a trainer is rotated and banked in response to unequalthrottle Settings, the nose of the trainer will drop, thereby simulatingthe corresponding responses of a plane in actual flight.

Another object of this invention is to provide means whereby when such atrainer is made to rotate and bank because of an unequal throttlesetting, a rudder loading may be placed upon the rudder pedals in thesame manner that a rudder loading occurs in a plane in actual flightunder similar circumstances.

A further object of my invention is to provide in such a, trainer a pairof simulated throttles, a differential device operable thereby to bemoved in response to relative movement of the throttles and turning andbanking means operable by the differential device.

It is another object of my invention to provide in such a trainer a pairof simulated throttles, a differential device operable thereby to bemoved in response to relative movements of said throttles, turning andbanking means operable by said differential device and independentcontrol means for restoring the banking and turning means to theirnormal positions independent of the relative positions of saidthrottles.

It is a further object of my invention to provide means whereby the"turning of the trainer in response to the relative throttle positionsmay be diminished by a banking of the trainer in response to the usualbanking means in the trainer.

Other objects and advantages will become apparent as the descriptionproceedsreference now being made to the accompanying drawings forming apart of this application and wherein like reference numerals indicatelike parts. In the drawings,

Fig. -1 is a side view of a trainer in which this invention isparticularly useful, certai parts being cut away for purposesofillustration.

Fig. 2 is a diagrammatic illustration of the principal parts of thisinvention.

Fig. 2A is a detailed .viewof one of the parts of my invention. L

Fig. 3 is a detailed perspective view, certain parts being shown insection, of the air speed regulator bellows.

Figs. 4, 5, and 6 are detailed views of the parts of one of the valvesof this invention.

Fig. 7 shows the parts shown in the three preceding figures in assembledrelation.

General description of trainer Referring to Fig. 1, it will be seen thatsuch a trainer comprises a fuselage l0 mounted upon a universaljointdesignated. generally as I 2, the lower part of this joint beingintegral with a central supporting member l5. Two pairs of bellows knownas the aileron (banking) bellows and the elevator (climb-dive) bellowsare provided. The aileron bellows aredesignated in Fig. 1 by I6 and Il,the former being the left banking bellows and under the left side of thefuselage l0 while the latter is. the right banking bellows :andiis underthe right side of fuselage ID on the side of universal joint [2 oppositebellows l6. 7

Turbine 20 provides a source of vacuum and by means of suitableconnections supplies vacuum to the central port of a valve known as theaileron valve. This valve when in its normal position applies an. e ualamount of vacuum to bellows I6 and I1 and, therefore, the trainer islaterally level, but if the control column be moved as the controlcolumn in areal plane ismoved to back the plane to the left, the aileronvalve is moved in such a manner as to admit vacuum to left bellows IGand 7 atmosphere to right bellows l1, causing bellows it to collapse andbellows l1 toegpand and the trainer banks toj the iear A movement of thecon- 7 trol columnin the trainer in the opposite di-' rection beyond itscentral position through similar functioning causes the trainer to bankto the right. a V

Another pair of bellows (not shown) known as I the elevator bellows areprovide'dyonehf these bellows being under the front of the'fuselage land the other under the rear. Upon" the .ipushing forward. of thecontrol column the elevator valve is moved, admitting vacuum to thefront elevator bellows and atmosphere to the rear elevator bellows, andt'he'tr'ai'ner assumes a-d rivin'g' attitude.

1 A pulling to the rear of the control-column re-V V verses theapplication of va'euum and atmosphere and-the ramer assam s a climbingattitude.

'fljliere :is also" connected to the'trainer fuselage by means'ofextending-arm 2331a 'turning'motor 2 2, the: outputshaft of which"has a'pul-ly' 25 fixedly mounted thereuponi "The main support 15 of thefuselage l Qhas itslower end 21 rotatably mounted in a receiving'memberfflwhich is afiixedto cross member t lcf stationary base 3 3'; Afixed pulley wheel 35 ista'lso ri idl 'mounted upon the cross 4 piece 91 p endlessbelt 2 is placed around this fixed p le'ywheel as wella's'around the wheele25 on "theierid .of the'sl iaft' ofsai d turningmotor 22; The'turning motor 22: is also connected to the sourcedvacuumi2'Q','there being inthe' connecting means" a mdder valve which isoperatedby the rudder pedals 192) and [94; in the trainer;Whenthestudent in' thetrairier' applies either foot to one of the rudderpedalsitherudder'valve link (tobe later described) is moved and therudder valve'jjis positioned sothatreduced air- 1 pressure :is admittedto the appropriate side of the turning. motor {which "'s in reality a'doiible acting *air 'r'notor) anfdf oxitpnt shait of'th e turning motoris rotated thereby rotating the pulley '2 5 fixed thereto; The endlessVbeltcZI wraps around the f xedjpulley" 35 which is afl'iXedto'jsta'tionary "base i733 and the turning motor is mounted upon arm 2;which is affixed to 0Cl a0n1 which in turnfis affixedto rotatablecentrsrsupports 15 and 2 1; When outi put wheel 251srotatd"in;resporiseit'orudder pedal movements the jfiictionbetfween thelarge fixed pulley swa m belt 2 I" prevents any slip page and so wheel25 travels-along belt 2 l causing motor 22;, octagon t8; bellows-lfiand'l'l and fuselage ill] to turn above stationary base 13:3. l

the 'rrfeg irig'it "be realized h t the r ih u e ge e'dseebfitie e fm yb made to dive;- cliinb bank and; rotate in simulaf tion of the diving,climbingQ banking and turnin 'A i' lhefi ih means rm n f a 'i i the wearwarm r ceptin combination with'me'ans to be later deof; a real p ate inflight.

scribed, anemia detaileddscription thereof ref erencefis-made toIU'. 'SLP;-1-,8 25,'4'62 and 2,699,851

rt'winite "realized that mail airpmn there is provided an altimeter"whichindic'ates th height of 1 1137 face aswell-as averticalspeedfindicatorwhich h l e; at were m aeiwnari eehas is gainingorlosin'g altitude, or'whetherit is in' leveljfh htpoSitiISn'LIn'theeventthat the plane plane i i'snown by p t These vtwol'instrumerits in a real time sureof the atmosphere whi chsurrounds them,

nfthecorrectidirection;

ne abov'e somlpoint'onthe earthfs 'sur responsive' to the pres: 1 a

lose altitude pressure the altimeter being responsive to the absolutepressure and therefore indicating the height of h rl ea ve sein nt hecar es su andthe vertic'alspeedind atoflbein esponsive tothe rate ofchange o'ftliepressure 'o'fthe atmosphere' surrounding it,- shows therate of J change of the altitude of the plane. 7 V ".Th'e altimeter in aplane has an indicating handiwhich moves across the dial a distance pro-.portionalfto the change in atmospheric pressure, and hence,proportional to the change in the al-' titudeoft-heship. The verticalspeed indicator has a hand which remains in the horizontal posi tionwhenthe atmospheric pressure is constant, thus indicating that'the'plane is in level flight,

this hand-movingnpward when*theatniosphei ic ressu e is ecreasing; errormoving "downward whenthe atmosp eric'pressure is-inc'rea'sin husindicating that "the-plane is gainingfor lo titude,respectively'. r

V .Asbefore implied, the trainer of the grounded, beforelherltiohfl,although it be Clififliif' mg 5 dit agattjituseees iidtactuau: gal-iner" n such a trainer advantageous to install i A s 'eedindic'atortondialtinieter antl- 'a vertica the assumed e iangieox tr theseinstruments n the? show the assumed H t faine" altitude assumed rateofcl engeoi sucl wil-Ishow l r of change thereof;

ea he s ".fl neffq loftinie that the 'I l'an'e hesitate its $11 icessive attitudes nd n ttle setting s isince the o e se i in I 'T. e leat a i the trainer at-a-rgiven moment is also made to depend "upon theseame factors the train r, Y

If the wa t r; as u es a dilemm ttitud e hrqt ett earsma eiz e aqenstanat rares re.v within theta-n1 decreases; the totaldecrease depending uponthe angle of climb and-the length of -time the trainer remains in itsclimb-ingposition. ihej'total decrease ingpressure within the tankattracts the "altimeter whiTchTgivesjth a'lti- V tudeoff the plane."rate'of decrease at any,

given moment; throttle setting not *considredji will depend upon theattitudebfithe trainen'zfand the vertical speed indi'catorwillirie's'p'ond'r tenni factor. *Ofcourse', if thetrainerassumes'a' diving;attitude the pressure withinfthe tankis built up accordingto the samerules aridthefinstruments respond accordingly; '7 V a e Also, if'thethi'ottle in the tr'ainer'is opened, the trainer attitude remainingconstant', the pres'-' sure within the "equalizer"tank is creased, the Vease-depending'updnthe I op mg tweeter-tineas we r a lengthef tihie thatthe throttlerelnafihs -615Gb. Tll iait N ever theles's, it has beer-1'of'change depends upon theyamountthat the throttle is opened. Thealtimeter and vertical cludes most of the detailed parts of thisinvention, 1

said apparatus for the most part being inside trainer fuselage l6 andresting on platform 31, as seen in Fig. 1. A manifold 24 is connected toa vacuum pump (not shown) referred to in the art as the altitude pump,by means of tube 26 and, therefore, manifold 24 always contains reduce-dair pressure. By means of connection 28 the manifold 24 is connected toair speed regulator bellows designated generally by 36. Air speedregulator bellows is in turn connected to air speed instrument 32 bymeans of hose connection 34.

In Fig. 3, the numeral 36 refers to air proof bellows preferably made oflight metal construction. This bellows may be mounted in any suitablemanner upon a frame member 38 which in turn is mounted on the platform31 of the trainer fuselage [6. Within bellows 36 is a needle valvedesignated generally by 39 and comprising a seat 49 and a needle 42.Seat 49 is rigidly ailixed to frame member 33 while needle 42 isattached to extension 45 of plug 43 which is screwed in theend 4'! ofthe bellows. Link 44 is also screwed into plug 43 as shown. It will beseen that link 44, spring 46, link 48, and extension 59 complete theconnection from needle 42 to lever 49.

When the lower part of lever 49 is moved to the left in Figs. 2 and 3,link 48, spring 46, and link 44 will move likewise and the left end 41of bellows 36 will be pulled to the left. Bellows 36 will therefore beexpanded and at the same time needle 42 will be pulled from its seat 49and reduced air pressure'from the manifold 24 will be applied throughconnection 28 to the bellows 36 and by means of connection 34 to airspeed instrument 32. The detailed construction of air speed instrument32 forms no part of the instant invention; rather it may be of anysuitable wellknown type providing it has an indicator hand whoseposition varies appropriately as does the pressure within the bellows36. As the pressure within bellows 36 becomes gradually reduced throughthe action of vacuum source 24, bellows 36 gradually collapses therebydrawing link 44 and the members connected thereto with it to the rightin Fig. 3. This gradual closing movement continues until the atmosphericpressure within bellows 36 and the tension of spring 46, both of whichforces tend to expand bellows 36, exactly equal the atmospheric pressureon the outside of bellows 36, which latter force tends to collapse saidbellows and thereby close needle valve 39. When these opposing forcesare balanced, vacuum source 24 will exhaust from the bellows the sameamount of air that enters through bleed hole 52 in line 34;

Because of the above equation of forces, by varying the tension uponspring 46, the amount of vacuum necessary within bellows 36 to balancethe atmospheric pressure on the outside of said bellows may be varied.The varying vacuuni' within air speedregulator bellows 36 will in turnvary the reading of air speed instrument 32. Hence, by moving the lowerend of arm 49 to the right or left in Fig. 3, the tension upon spring 46will be decreased or increased respectively, and the vacuum withinbellows 36 will correspondingly be decreased or increased. I The greaterthe vacuum the higher the reading of air speed instrument 32 whichindicates the simulated air speed of the trainer.

Functioning of instruments in a simulated dual engine trainerTwothrottle controls 54 and. 56, assumed to be associated with the leftand right engines of the trainer, respectively, are provided. Thesethrottles are mounted upon any suitable part appropriately located inthe interior of the trainer. It will be noticed that the lower end ofthrottle 54 has pivotally connected thereto a link 62 which in turn ispivotally connected to the upper end of a bell crank 64 which ispivotally mounted upon any suitable part of the interior of the trainerfuselage l9. Pivotally connected to the other end of bell crank 64 isone-end of a rod 66, the other end of which is pivotally connected to across piece 19, Cross piece 16 is rigidly aflixed by means of screws 14to the outer leaf of a 3-leaf valve designated generally in Fig. 2 as12. This 3-leaf valve, which will later be described in detail, ismounted upon a hollow shaft which extends through all the leaves andwhich is rigidly affixed to a sliding member 11 which is free to slideup and down in a track designated generallyby 19. Pivotally mounted uponthe central portion of cross piece 19 is the upper end of link 18, thelower end of which is pivotally attached to oneend of arm 86. The otherend of arm 86 is rigidly affixed to shaft ,82, which runs transverse ofand which is pivotally mounted in extension 83 of platform 3! in thebottom of the trainer fuselage. On the other end of shaft 82 is rigidlyaiiixed-armflfl, to the upper end of which is pivotally connected link96. The other end of link 96 is pivotally mounted to the central portionof walking beam 56. This walking beam is pivotally attached tohoriozntal stub shaft 5| at the point 53. Also pivotally attached tolever 56 is link the other end of which is likewise connected to arm 49at a point above the pivot 51 of arm 49, Pivotally attached to arm 49 atthe other end is extension 59 and link 48, to which reference has beenpreviously made.

It will be recalled that any movement of the lower end of arm 49 to theright or left in Fig. 2, through the action of link 48, spring 46 andthe needle valve 39 shown in detail in Fig. 3 will result in a change inthe reading of air speed instrument 32. By referring to Fig. 2, it willbe noticed'that the movement of throttle 54 in either direction willmove link 62, bell crank 64, and link 68 will be made to move up Or downdepending upon whether the throttle 54 is moved rearward or forward,respectively. This movement of link 68 will be transferred to crosspiece 10 and therefore, the 3-leaf valve 12, the left end of cross piece10, and slide 77 will be made to move in the same direction as themovement of link 68, slide 11 moving in track 19. The right end of crosspiece 16 will pivot on the point where it is attached to link 69. Thiswill impart a like movement to link 18, and the right end of'arm 86 willbe made to move up or down, This will cause shaft 82 to turn one way orthe other,

amazes" will in turn cause dink!!! to recipnacate.

arm

the position of link "48 hence the tension. upon spring 46, whichspring, as outlined' above',

governs the amount of vacuum within bellows 36. This amount oi vacuumdetermine'sthe reading of air speed indicator-32.

Theindicator attached; to air speed instrument 32 is constructed so thatthe-*greaterthe vacuum within bellows 36 the greater isth'e indi catedair speed. 'By a corrsjide'ration ofthe link- V .ran'gement. of'arm. 50,link '55, andthe'lever-M 7 115- ages j ust discussed, it will beseenthat a-pushing to the left of throttle '54, which action simulatesan increase or opening of the throttle of the 7 assumed: left engine,the lower 'end of arm 4} is made to move 'tothe l'eft in Fig: '2'andflthereiore;

thetension upon springfifibecomes greater. The

vacuum within bellow-s36 will-therefore become greater, and so Will'theindicatedair' speed of the trainen As throttle 54 is moved to theright-in Fig. 2;, simulating a decrease int-he throttle settingof,theassum'ed left engine, it wili-be-reflliledth'aJt the lower end ofarm49 will;move to the right in -2 and the tension upon spring lfiw'jllfbecome less and the vacuumwithin bellows -will also be lessened.This increase in pressure will cause a corresponding decrease in theindicated;

air s'peedof the trainer.

;A change inthe setting ofthrottle 54 does n'or cause an instantaneoustotal change in the in;

dicated' airspeed, but instead, the changedthr'dt tlesetting causesa-gradualchange in thevacuu rn within bellows ,36, and therefore, agradu'al change in the indicated-air speed; This simulates'the gradualresponse of the air speedindicator of a plane-in flight to achan'gedthrott-lesetting,

It can beseen in Fig. 2 that a change, 'in the setting of-throttle 56will-produce a change they indicated; air speed in the same manner as achange in the setting of "throttle 54 because throttle 56; actingthrough linlflitgbell crank 35; and link 39, afiects crosspi'eceIllvalve {1 2 and link '18-'in the same manner thata similar movement ofthrottle- 54 affects these parts. Therefore, a'detailed description-oftheefi'ect of the throttle setting of the assumed-right engine of thetrainer. is deemed unnecessary.

A -movement of throttle 5'4 in one direction and an equali'butoppositemovement of-throttle 56 wilrproduce no change in theindicated 5 ainspe'edbecause the oppositemovements applied to hori- 'zontal bar H1,which acts. as. a differential, will: cancelroneanother andvalve 12,slide 1:1 and link i8. will neither be moved upnordownpbutra likemovement of both throttles =inithezsamei-direction will. result in achange in the indicated air-speed. greater than a. movement of; one.-Ofrthe ithrottles. because of the "greater. movement of;horizontalmember Mland link it; This:simulates-theme suits ofcorresponding settings o f:the. throttlescin.

a dual engine aircraft.

Itmay beconcluded, therefore; that 'mmrinvenr; tion provides; means -wher eby,the simulated air r speed -0]? a *dual'eng-ine rtrainer may-bemadewto 3 amw h'a han e he o e t ins-oi. ither' or b t i ees m d;. e ;nenthe aiueimam ierfihe h s l i ir? sofa dl li n fl fi lamr'li z 0 Hi ch/ct on; V r--- & &. th uehmpliers' 7 in liight varies with correspondingchanges in throttle F settings.

Furthermore, this invention provides means." whereby' the si-mulatedair-speed of a dual engine trainer may also be -made to varywith achange inithe attitudeoithe trainer. As seen infFig. 2, horizontalshaft2110: is mounted for rotation in brackets 212 (only oneof which isshown) which 7 are fixed-lyattached. tothe platform 3.! onthe trainer'fuselageyl'fl. The left end of shaft 2 l 0?is.-

rigidly aflixedto; arm 214- and to the upper endof this arm is rigidlyaflixed stub shaft 5!, to which reference has been previously made. 'Thearhasfbeenr previously explained. V 7

To the right end of shaft, 2H]; is fixedly con.- nectedpitch action armZlfiwhich has a roller 2Z2su-itably mountedupon the lowerfend-thereof.

Attached to the upper 'end, of arm 21% is spring 22,8,theother-endofwhich, is, attached to a part affixed-to p1atf0rm 3'; Because-"0f. his nv merit; it will be understood that'spring 228 at all times maintainsroller- 222 lQQIltfiCt. with cam,

As seen in Figs. 1 and'2 platiorm 3 1, brackets 212 and: all oftheotherparts rmounted' uponplatform 31, as seen in Fig. 2, are suspendedbelowun-iversal; joint; I52 by'means of members 232. Whenever thetrainer fuselage l-il' pitches in simulation of the climbing'oi-aplanein actual? flight, the

platform 31 also assumes aclimbing: attitude and: 7

itswings ahead of its leve1:fiight; position; carrying with it brackets2il2and-all.'or-theother'members 'affixed' thereto, Roller, 2'22 cannotmovefjorward because pitchaction cam22jfl engages it; Bracke 2 ZI-ZE,-(nly--one of; which isshown) therefore trim/.6v -Witli1,=respect.tpypitch action. lever 2 l6 as ho h. rolle 2:2 'dzthe ower e d of l vr-Z116 were pushe owa dth -rearf fusela M; -e-, othe t shtfi F a-=24he-upper d fza'rm 2M and stubgsh 5kthereforemovetoward the head ofthe-trainer'fuselage as does the upper end of armwhich in thisyinstancepivots about the point; where, link" 90. attaches thereto, Link andtheupper end of; lever-dimove ahead and the bottomof lever-Q9 moves 'to:the ream-decreasing the. tension upon springdii; This. resultingdecreasein-tensionallows the atmospheric pressureupon-theoutside ofbellows 3fi-tocollapse the bel-.

lows and; the. opening ofithe'needle valve therewithin. is. reduced, theextent of this reductionj dependingupon; the amount of change-in theat-- tituiifi (lithe trainer. Vacuum from manifold-24will-therefore-not:have ,a'sdarge an orifice to workthrgmgh andmore-atmosphere will enter bleed: hole-EZ'Tthan is. exhausted from the"bellows-by manifold 24-. Agradual-increase in-,-the-pressurewithinebellows-su willresult and a gradualde crease in the airspeed asindicated by' air speed indicator 32 willoccur 'lihe pressure-WithiHjbELrlows, 35 will increase-until the vacuum withinbellowatfi,equals the tension upon spring-4B;

Whenthispointisreached; thefvacuumsource willexhaust from thebellows thesame amount of air;as entersthesystem bymeans of bleedhole 52.." O h thr hand i-th q r ner --f s a Hr is gpitched in; simulation-oh the divingof' a planeual fl ht lat orm-t ist sumes a'd vins att tudea dal es iehind its-level ht positio a rvinsw t z t r ck s z za a he parts mountedthereupon Tensionspringdm =pu ce;- n nhe mwfrbitch act o ever: H6 mimainsm er 2. 1 n: c nte tr th l i chzactionr m lil aracbe siz i herfcre; .-.e -withsre.-

I 222 and the lower end of the lever were pushed toward the head ofthefuselage I0, i. e., to the left in Fig. 2. The upper end of arm 2I 4and stub shaft 5| therefore move toward the rear of the trainer fuselageas does the upper end of arm 50, also pivoting in this instance aboutthe point at which link 90 is attached thereto. Link 55 and the upperend of lever 49 move toward the rear, the bottom of lever 49 movestoward the head of the fuselage, increasing the tension upon spring 46.The size of the opening of the needle valve within air speed regulatorbellows 30 is therefore increased and the vacuum from manifold 24decreases the pressure within this bellows. In response to thisdecreased pressure, air speed indicator 32 will indicate an increasedassumed air speed.

It should be noted therefore that a climbing attitude of the trainerfuselage decreases the tension upon spring 46 and a lower indicated airspeed results while a diving attitude of fuselage I0 increases thetension upon spring 46 and a higher air speed is indicated.

From the foregoing it will be realized that my invention provides meanswhereby the indicated air speed of the trainer may be changed by anopening or closing of either or both of the throttles and by a change inthe attitude of the fuselage in simulation of the changing of theindicated air speed of a plane in actual flight in response tocorresponding movements.

In an airplane in flight, whether it carry one or more engines, achanged throttle settin will cause the plane to change its altitude-anincreased setting causing the plane to climb while a decreased settingwill cause the plane to lose altitude. N 0 change in the attitude of theplane necessarily results from a change in the throttle settingthechange in altitude may be caused by a difference in the lift resultingfrom the change in air speed, of the plane. Inasmuch as there is achange in altitude resulting from a change in throttle setting, thealtimeter as well as the vertical speed indicator in a plane willreflect this change. The following means have been incorporated in thisinvention to produce the correct response of the altimeter and thevertical speed indicator to a change in throttle setting in a dualengine trainer.

Referring to Fig. 2, an equalizer tank 92 has connected to it by hoseconnections 93 an altimeter 94 and a vertical speed indicator 96.Altimeter 94 shows the simulated altitude of the trainer, its readingvarying with the atmospheric pressure within tank 92, the lower thepressure the greater the indicated altitude. Vertical speed indicator 96simulates in appearance the real instrument of the same name used inactual flight, when the atmospheric pressure within tank 92 isdecreasing the vertical speed indicator moving in a clockwise directionfrom the level flight position, thus indicating that the trainer isgaining altitude, and moving in this direction a distance correspondingto the rate of change of altitude. On the other hand, when theatmospheric pressure within tank 92 is increasing, the opposite resultoccurs, thus showing the fact of descent and rate thereof. It istherefore evident that by changing the atmospheric pressure within tank92, the altimeter 94 will show the simulated altitude of the trainer andthe vertical speed indicator 96 may be made to show the fact of ascentor descent and. the rate thereof.

Equalizer tank 92 is connected by means of hose 98 to one of the portsof climb Valve I00 and to one of the ports of dive valve I02. The port I0| of climb valve I00 is also connected by means of hose I04 to manifold24, while the second port I03 in dive valve I02 runs directly to theatmosphere. The detailed construction of the climb and dive valves formsno part of this invention and for a detailed description thereofreference is made to the above-mentioned U. S. Patent 2,099,857. Inorder to understand the instant invention it is sufficient to know thateach of the valves I00 and I02 is a needle valve, in the case of theclimb valve I 00, the needle and seat being between the port leading tothe equalizer tank 92 and the port IOI leading to the manifold 24; andin the case of thedive valve, the needle and seat are between the portleading to the equalizer tank 92 and the port I03 which opens into theatmosphere. Connected to the needles in each of the valves is a threadedstem, the outer ends of which are designated by the numbers I06 and I08.The threaded stem I06 works in the interior of climb valve I00 which isthreaded for the reception thereof, while stem I00 is likewise a part ofdive valve I02.

Fixedly connected to the end of threaded stem I06 is an operating arm H0and a similar member H2 is likewise connected to threaded stem I00. Eachof the operating arms II 0 and II 2 is pivotally connected to one of thepair of blocks I I 3 and I I4 which are slidably mounted uponreciprocating member II5. A pair of stops I23 are fixed to the front ofmounting I21 upon which the climb valve I00 and dive valve I02 aremounted. When arm H0 is in the position contacting its stop I23, climbvalve I00 is closed and when arm H2 is in contact with its stop I23, thedive valve I02 is closed. Movement of arm I I0 to the right in Fig. 2opens the climb valve I00 which is right-hand threaded, while a movementto the left of arm I I2 opens the dive valve I02 which is left-handthreaded.

Fixedly attached to the central portion of member II5 between blocks H3and H4 is a stop I I1, so when member I I5 moves to the left in Fig. 2,stop I I7 likewise moves in that direction carryms before it block I I4which in turn carries arm II2 to the left, thereby opening dive valve I02 and permitting communication between port I03 leading to theatmosphere and equalizer tank 92. At the same time, spring H 9 willremain in its normal state, but spring I2I will be contracted becauseblock I I3 and arm IIO remain stationary because of the presence of stopI23. Therefore, such a movement will not aifect the position of climbvalve I00. However, a moving of member I I 5 to the right in Fig. 2 willopen climb valve 'I 00, thus admitting reduced air pressure to theequalizer tank 92, but this movement will not affect arm IIZ of divevalve I02, and therefore, dive valve I02 will remain closed.

Referring to Fig. 2, it will be recalled that the lower end of arm 50moves to the right when either of the throttles 54 or 56 is opened, saidarm pivoting about the point 53. It will be seen, therefore, that anopening of either of the throttles 54 or 56 will cause link II6 whichispivotally connected to the lower end of arm 50 and member II5 which isconnected to link II6 and stop I I1 to move to the right, thereby movingthe lower end of operating arm IIO to the right, opening climb valve I00and admitting reduced air pressure from manifold 24 into equalizer tank'92. The atmospheric pressure within equalizer tank 92 will thereforebecome reduced and the altimeter 34 will indicate a higher altitude andoi vo t 99 remain -esteem w ese t e er w mags.

' of arm 50 th eni esms indi ator housem te tri rhe longer climb men-tand a e t ereo be em h aemimw thih ta k 2 2; and he e tore. gr ater wilbat e in.di teda ud h therham a ecrease zth s t inao ei her th tt egffl. o Wi u ethe-1o en .o arm-.ti to-move o th zle t Fi 12 and L n tie d-.5 willl ew be mo ed to t e eft lih aneedle valve in c im valve 30 willr mai clos d: but the va v in dive valve 192 will ope allowin ounication. between the atmosinheric port 103 and the equalizer ta atcauseof. .the cancelling effect of the opposite movements f bar 151.,but a given movement of both throttles in. the samedireotion willjha-veagreater efieet than, a like. movement of. but one throttle. The not"change in; the positions of Y the center .oi' difi'erential bar *l-il.and link .18 from .their'levelfiflight positions. controls the rate ofclimb. or descent as shown by verticalspeed in .dicator 9.6; while thelength. of time that such a .ehangeremains in efliectoontrols:theamoun-tof.

total.changein.altitudeindicated by altimeter 94. *It will herecalled-that if either throttle is opened, air speed indicator. 32shows an increased lindicated' air speed. .This same movement opensclimb valve I08 and therefore vertiealispeedindicator :ofijand altimeteras show theiact. f ascentandztotal chan einaltitude Qn the other :hand..aclosing of either throttle. causes air-speed indicator 1.32:: to show1 a falling off; altimeter at shows; alossof altitude. and verticalspeediiridiea- .tor showstherate. of descent, It will. therefore berealized that air speed indicator 3 .altimeter. Maud vertical speedindicator 4 .6. work 1120-. gether. as do. their counterparts in arealplane.

Thisiinventionrtherefore providesbvfi fore- -going describedarrangement, means; wherebythe vertical speed indicator and the.altimeter in a dual. engine. trainenrespond. to. a. chan e n. ththrottle settineof eitherorzbothof theassumed fplane. respond: to a,correspondingehange in the throttle settingsof: a plane'inflighti andalso. that the. iunctioningof these instruments.- is. properlycorrelated with the. functioning of.--th e. airspeed indication;

u hermore, this invention provides means wherebytheve'rtical speed.indica or. and the altimeterinra. dualenginetrainer maybemade tohrottlestbut to. a change-in arts or both. or; t

seats-.5 I;

.eon to o inking Ti e ower end 11: will: mov o. t ri h where aseaaoeengin'iesjust'ias. the.samepinstrmnentsqin .a .real 7 i the; attitude.ofxthei ra e fuse a e. s w ll; as

willnowbeexplained. i r

' lbe re alled that Whe ever t t a n itchesnsimi -la on cl mb ng. st b T-.-be.;m.eve' z toward he-fr nt f h ,before explained, this vverticalspeed indicator 9fi toregister'the amolint :thetrainer. e I

Turning and banking of trainer in responsc1 'to will cause altimeter.fifikand of. ascent andthe rate thereoi.-

1 0n the other hand, if the trainer ima es n: A be pitchedin-simulationoi .adive, shaft am; will be moved. to the rear of itslevelflig vt position.

and stub .sha t .51 .will movetowardltherear of the trainer or to therightinFig/Z. LinkQlHi will thereforebe moved towardthe front of .the"trainer or. to the. left in Fig. 2 and dive valve 11.02 will. beopened. Altimeter-- 9.4. and vertical. speed indicator will thereforereflect .theohangain altitude and rate thereof;

Therefore, this to the changes in the throttlesettings-.thei1einbutrespondas wellto aohangein therattitude of digjere'nces. simulatedmotorispeeds In a. dual engine pl'ahe which i irlthe level ightpoitiomif neofithe ,engine i making a greater number of revolutionsperiminute han the oth r the. plane will tu ward t Side Of he slowerengineisv turning, and as e result.- ofother factors, the tu ng'produeedb theoifferent engine speeds is "accompanied by a banking ofthe plane. j The d fiereneein engine speeds which brings about theseresults is .usually produced by unequal throttle .settines..- Thefollowing means, have been ncorporated-in thisinvention,sothatflwhethere isan unequal setting of the throttlesL the 7 trainer will .turnandbank, in'. the samemanh'er that a plane in flight. under the samecircumstaneeswouldturn and bank;

Referring to. Fig. 2, it. will be recalled, that whenever throttle.54.;is" moved to the leftor right. in Fig '2. the, end

down crop respectively and a. similar movement results at. the .endofbar-'1'!) to which inkgea'is connected whenever. throttle 56-.is movedto the leftor rightinFig. .2. Reference is novvmade to Figs. 4; 5, 6,and (which show in .detaiLthe construction of Fig. 4.. shows in -detailthe lconstruetionoii the leaf I30, which is thesleat towardv the frontof the trainer-as. seen in Figs. 1 and 2. it wil-ilzbe f seen that thisleafhasl a central port L32 extendin-g completely therethrough, and acounterbore i3 4 extending a substantial distance. into the rear face(face. toward rear-of trainer) oflth-is valve connects with central'port1.32. Ports J36 and l38fextend eompletelythrough leaf J- 3O so thatthey'are at all timessin communication with the atmosphere V i V r V Rigidlyafiixedtothe iront fiace (-face toward 7 head of M53, as shown in Eig. 7is an. uipstanding arm 1.42, As shown in Fig.2, to the upper endof arm 7M2 i pivotally connected link lM. I eafv I 3.0. is rotatablyl mountedupon meow. shaft I46 which is connected to a vacuum supply linesl48whiehalso connectsto turbine. 20. It willibe realized,

therefore, that vacuumenters hollow shaft M6 and throughxport 1 5i].in.hollow-shaft [46' manitests itself atlall-times inlcounterloore I34which is in contact with the front faceofleai 152', as seen in Fig. 7.Atmosphere; atall timesenters orts L35 and I-BitandJikeWiSeiS.in;.contaetiwith invention provides .means 7 whereby theverrticalspeedvindicatorandtheraltimeter in a dual motortrainennotonlvmspond Furthermore; h causeanyplanewill.automatioallybank, whenit V of horizontal bar llllto awhich link .63- is pivotally. connected will-move the lz leafvalve-which is-desig nated generally in 2: the snumbeeii'.

trainer): of leaf I30 by means -of screws 13 the front face of leaf I52. A plug I54 is in the end of hollow shaft I46 so that air may notenter that end. Within plug I54 is a threaded member I56 to the outerend of which is pivotally attached the upper end of link 18.

Fig. shows in detail the construction of middle leaf I 52. This leaf isalso mounted upon hollow shaft I46 but cannot rotate thereupon becauseof the presence of set screw I58. It will be seen that this leaf has aport I60 which extends completely therethrough and which is in perfectengagement with the counterbore I34 of leaf I39 when leaf I30 is in itscentral position. Fig. '7 shows leaf I30 in its fixed position. Twoother ports I62 and I64 likewise extend completely through leaf I52 andare also in engagement with the ports I36 and I38 when leaf I30 is inits normal position. Ports I63 and I65 which are in the rear face ofleaf I52 and therefore adjacent the front face of leaf I66 extend asubstantial distance within leaf I52 and then turn at right angles tocommunicate with hollow fittings, I11 and I19 mounted in the ports.Connection I81 extends from fitting I11 to the right aileron bellows I1while connection I89 places the left aileron bellows I6 in communicationwith fitting I19. When leaf I30 is in the central position, therefore,reduced airpressure will be present in port I60 and atmospheric pressurewill be present in ports I 62 and I64. All three of these ports are inengagement with the adjacent front face of leaf I66, as seen in Fig. 7.

The construction of leaf I66 is shown in detail in Fig. 6. It will beseen that rigidly affixed to the outer face of this leaf by means ofscrews 14 is cross bar 10 which has been mentioned several timespreviously. Two ports I63 and I10 extend from the front face of leaf I66adjacent center leaf I 52, as seen in Fig. 7, a substantial distancewithin that leaf and then turn at right angles to communicate with thecircular periphery of this leaf and hollow fittings NH and I 63 mountedtherein. In the upper part of leaf I66 are two ports I61 and I69extending completely through this leaf and a counterbore I1I whichextends a substantial distance within the front face of leaf I66adjacent the rear face of leaf I52 and connects with the vacuum supplyinside hollow shaft I46 by means of port I13.

Whenever bar 10 is in the horizontal position, port I68 in the frontface of leaf I 66 slightly overlaps Vacuum port I60 of leaf I 52, andport I68 lies adjacent port I62. as shown in Fig, 5. At the same time,port I10 slightly overlaps vacuum port I60 and lies adjacent port I64.Therefore, whenever bar 10 is in the horizontal position as shown inFig. 2, a slight amount of reduced air pressure will be admitted to theports I68 and I10 and, therefore, to connections I12 and I14 which areconnected to bellows I16 and I18, respectively. Also, whenever bar 10 isin the horizontal position counterbore I1I in the front face of leaf I66is completely covered by that portion of leaf I52 between ports I63 andI65 and therefore no vacuum is supplied to connections I8! and I89 whichconnect ports I63 and I65 with the right aileron bellows I1 and leftaileron bellow I6, respectively. Port I61 is then to the left of portI63 and port I69 is to the right of port- I65. Therefore, whenever bar10 is in the horizontal position the vacuum always present incounterbore I 1| will not be applied to ports I63 and I65 and,therefore, will not be applied to the connections I81 and I89 which gofrom the outlets I 11 and I 19 to the aileron bellows I1 and I6, respec-14 tively. Atmosphere will not be applied through either of the portsI61 or I69 to ports I63 or I65.

Bar 10 is in the horizontal position only in case both throttles 54 and56 have a like setting and, therefore, whenever these two throttles arethus set, rudder pressure bellows I16 and I18 will remain in theirnormal positions as will the aileron and banking bellows l1 and I8.

However, in the event that the setting of throttle 54 differs from thesetting of throttle 56, bar 10 will no longer be maintained in itshorizontal position and in moving therefrom it will rotate leaf I66 andport I68 will communicate with port I62 of leaf I52 or to a greaterextent with port I60 of the same leaf, depending upon the direction ofmovement. At the same time, port I10 will communicate to a greaterextent with port I60 or with port I64. This communication will cause amore than normal amount of vacuum to be applied through port I60 of leafI52 to one of the ports I68 or I10 while atmosphere will be appliedthrough port' I62 or I64 of leaf I52 to the other port, causing excessvacuum to be applied to one of the connections I12 or I14 and atmosphereto be applied to the other. Therefore, one of the bellows I16 or I18will be affected by the atmospheric pressure which will enter and theother will be affected by the applied vacuum. One of the bellows willtherefore contract while the other will expand.

Referring to Fig, 2, the side I86 of bellows I16 toward the front of thetrainer is rigidly affixed to anysuitable stationary part of thetrainer. The rear side I82 of this bellows is the movable side and hasconnected to its top by suitable pivotal means a link I 84 which has itsother end likewise attached to the left end of rudder bar I86. It willbe appreciated that as bellows I16 'expands and contracts, side I82 willmove back and forth and rudder bar I86 through the action of link I84will be made to pivot about point I88. This movement will affect theposition of link I90 which connects with the upper rotatable section ofthe rudder valve designated generally by I9I.

Bellows I18 is similar in all respects to bellows I16 and is connectedto rudder bar I86 by means of link I85. It should be noted, however,that a contraction of bellows I16 has the same effect upon rudder barI86 and link I90 as an expansion of bellows I 18. I

The central port of rudder valve I9I is supplied with Vacuum by means ofconnection I93 which goes to turbine 20 and each of the outlets I95connects to one side of turning motor 22. A movement of rudder valvelink I90 to the rear rotates the upper section of rudder valve [9! sothat atmosphere is applied to one of the outlets I95 and vacuum to theother, and these outlets are connected'to the turning motor 22 so thatthe trainer turns to the left. A movement of rudder valve link towardthe head of the trainer reverses the application of vacuum and air tothe outlets I95 and the trainer, through the reverse action of turningmotor 22, rotates to the right. The construction of this rudder valveforms no part of the inst-ant invention, and for a detailed descriptionthereof reference is made to the aforementioned U. S. Patent 2,099,857.

Rudder pedals I92 and I94 are rotatably mounted upon shaft I96 which isrigidly held by brackets I90, only one of which is shown. If rudderpedal I92 is pushed forward, link 296 which is attached to this rudderpedal at a point below shaft I96 will move to the rear, the left end'tion of the assumed slower engine. 7 V 7 t will be appreciated thatsetting throttle 54 A of rudder h I86 will move in the same direction, 1

and'lin'le I 9!] will move to the rear, thereby'turne ing. the uppersection ofthe ruddervalve,"vac'u-um is applied; to one of theoutlets-I95 and atmosf phere to the other, and thence to the turningthetrainer will turn to the-right It is tolbe noted 7 that an expansionof, bellows I'ISVand a contraction of bellows IIrS affects rudder'valvelink 1% and rudder valve I9! inthe same manner as though pressurewereapplied to rudder pedal I 92. On'the other hand,-'a contraction ofbellows I'Iii and an expansion of bellows I18 gives the same resultasapplying vpressure to rudder pedal I94.

Returning to valve 12, it throttle lid-be farther opened than throttle56, the end of bar 19 to which link 681is'connected willbe lowerthan theother end; of this bar. Valve section I6i5 will therefore be rotatedcounterclockwise, from its neutral ,positiomand. port I68, as showniinFig; '7, will contactvacuum port I60; of leaf I52 and, therefore,reduced air pressure will be applied through connection I'I'2-' to'thebellows II-S; At the same time, atmospheric pressure will enter port I-lIlfrom port- IE4 and; will be appliedthrough I connection I=14 to thebellows-- H8, Bellows H8 will therefore expand while bellows l-l-fi'willcontract, andilink I84 willpull'on the end of rudder bar 186to'which it is attached; while link I85 will push the other endof'rudder bar I86 in a "man-nor to rotate that member about pivot I88; 7

Rudder; valve link Hillwill therefore be, moved in the samedirectionas-though-pressure were applied torudder pedal 34,; andtherefore, the trainer will turnto the right i. e., in the directo amore closed position than throttle 56 will cause. port I'IIl of leaf I65to contact port I60 of leaf I352, while port I68; will be incommunicaI-' tionwith'port I52. Vacuum willtherefore-enter tube I'M andbellows IIBwhile atmospherewill therefore, that the foregoing meanscause the rudder pedals in the trainer torespondtol anun- 7 equalthrottle setting in the same max mum 1 the pedals ina real, planerespond mule sarnfeil enter bellows I"I6- through line I'I-2'. Theformer i bellows'will contract, link- I'85will pullthe right end ofrudder bar I toward the head of'the trainer and at the same time,bellows He will expand, pushing link I84 and the left end of rudder barI86 toward the rear, ofthe trainer. Rudder valve link I90 will likewisemove toward the rear and will afiect the ruddervalvepin the same manneras though pressure were applied-to rudder pedal I92 The trainerwilltherefore turn toward the left, again toward the side of: the slowerturning motor. :7 v

It will be realized therefore thatrmy. invention provides means forcausing an assumed dual engine trainer to turn inthe direction of theengine having the-assumed slower motor speed.

Not-only does a plane in flight turn toward'the weaker engine; but at'the same time the rudder pedals in the plane respond as, though'pressure"were actually being appliedto theruclder pedal on the'side' of theweaker engine;

It will be recalled that whenever vacuum enters 1 bellows I'lBandatmosphereienters bellows H3, is

the trainer is 'turneidto the, right through the aci t-ion of links I84and IBB; rudderbar- ISG-andruddervalveilink I99: "Referring-toFig. 2,;itwill be seen that; whenever this: condition prevails, the

right end, of rudderibar-'lfifi will move to the rear as will link 202which 'la's't linleWilI-Epullthe:bot-

tom; estens onrof; rudder: penal; I 94: to twhichsit. i

, aileron bellows 15 through ports I $9 and lgli Kconnected tothe, rearand; rudder pedal I34 {wil move as, though pressure were being-appliedthereto; At, the same time, the left en -er rudder bar I 86- will movetoward their o .t-rQf, the trainer as will link 2% and rudderv pedal{.92 will also move as though pressure were being applied, to rudderpedal I94. 7 It willbe realized,

circumstances. a IV 1 In a real planeinv flight, the turning cau's d} bydifferent engine speeds maybe overcome byf the pilotjs applying pressureto the rudder -pe'dal' on thetside of the stronger engine, Referring to2,pwhen'ever throttle 54L isopened to ag ,e

extent than. throttle I'I' B and vacuum enters bellows 1.16, link andthe rightendjofrud-de'r bar I86 moves. to the rear thereby moving ruddervalve link, use: toward the front er the trainer, and

motor. Theistudent in the trainer, byl a-pp his foot to rudder pedal I92will force-link the left end, of rudder bar resend. rudderva e link Hillto the rear, thus overcoming the turn ng of the trainer caused by theunequal tlirottle set-- the side of theslower engine causes thelane, to

rbanl; in the direction of the slower engine; jthe 1 following means areprovided in "my inventionto simulatethisaspect of actual flight.

Referring: back to the situation thatacallsedea collapsing of one of thebellows he or' na and:

the .expansionof the other, via, an unequaliset ting of the throttles 54and 56v and-theresu'ltant displacementof bar II! from thehorizontalqposition, it will be realized, thatwhenev'er this situationprevails, vacuum port III is in communication with one of the ports I63or, LE5, depending upon" which thrott e 54 or i 56v isth'e farther open,and the other port Ithorllifi will communicate V with the atmosphere'throughport. m or Ills.

Therefore, the connection I8l will'intrqducellac- .ruum or atmosphereinto Vthe-Vaileronibellowsfl l and the connection I89 will introduceatmos- V 'phere or vacuum into the Othefaile ron bellows will, beunderstood. that when hro s-it II, open farther than throttle 5B,.leaf}6.5- will'be turned counterclockwise from its neutral posr-V tion, asshown in Fig. '7, vacuum will'entefrjrig'ht aileron. bellows II froniportsl Il and Ita and connection I81 while atmosphere will ent'e" ftconnection I89; The left bellows will expand the right bellows willcontract,- causing thetr ner to bank to the right. Simultaneously-Qtymeans heretofore described, atmosphere erpands and the trainer is turned to theirigjht.

terp 56., atmosphere,enterslbellbws V V. V. ite eie n i ll wr theright,- that is, in the direction of the we r- V doesa-vdualengine-planeturn bellows I'I6fand vacuum contracts bellows I318;

closed position than throttle 56, the right end of bar 10 will belowerthan the left end, leaf I66 will be turned clockwise from its neutralposition as viewed from the rear of the trainer, and atmosphere willenter port I61, pass through port I63 of-the center leaf and by means offitting I 11 and connection I81 to right banking bellows I1. At the sametime, vacuum from port "I will enter port I65 and by means of fittingI19 and connection I89 be introduced into the left banking bellows 16.The resultant expansion of the right bellows and collapsing of the leftbellows .will cause the trainer to bank to the left. From the precedingdiscussion it will be recalled that when throttle 54 is more closed thanthrottle 56 vacuum is introduced into bellows I 18 and atmosphere intobellows I16, causing the trainer to turn to the left. Therefore, whenthrottle 54 is not open as far as throttle 56, the fuselage I is turnedto the left and is also banked to the left, in simulation of the turningand banking to the left of a dual engine plane when its right engine ismaking more revolutions per minute than its left engine.

From the foregoing it will be seen that my invention provides means in agrounded aviation trainer for simulating the banking and turning of aplural engine aircraft resulting from a difference in the speeds of theengines in the plane.

Furthermore, the rudder pedals in the trainer will respond in the samemanner that the rudder pedals in a plane in actual flight would respondand the student in the trainer may overcome the rudder loading just asthough he were correcting the same condition in a flying airplane.

Whenever a plane in actual flight is turned, whether from an intentionalturning by the pilot through rudder pedal movements or from a differencein engine speeds, not only does the plane automatically bank in thedirection of the turn but its nose drops down and the plane losesaltitude unless the pilot pulls back on the control column. The ruddervalve I9! provided in trainers of the type under consideration have anauxiliary set of ports, as described in the copending application ofEdwin A. Link and myself, Serial No. 457,692, now U. S. Patent2,358,016, dated September 12, 1944, so that whenever the valve ispositioned so as to rotate the trainer vacuum is automatically admittedto the front elevator bellows and atmosphere to the rear elevatorbellows and the trainer automatically noses down. Therefore, wheneverthe trainer fuselage I0 is rotated in response to relative throttlesettings two secondary responses of the fuselage occur, first, thefuselage banks in the direction of the turn, and second, the nose of thefuselage goes down.

The turning of a dual engine ship in actual flight caused by adifierence in engine speeds is diminished as such a plane is banked inthe opposite directionuntil, when a certain angle of bank is' reachedthe turning and resulting banking sov caused completely disappear. Atthe same time, the rudder loading which, as above described, accompaniesthe turning also disappears. Means will now be described for simulatingin a trainer of the type under consideration this phenomenon of actualflight.

Referring to Figs. 2, 4, and '7, it has been mentioned that an extensionI42 is aflixed to leaf I30 by means of screws I40. As seen in Fig. 2, tothe upper end of this extension is pivotally connected link I44, theother end of which is pivotally connectedto the upper end of'arm 242.Arm 242 thereto.

pivots about the point at which the shaft 246 is rigidly afiixedthereto. The other end of this shaft is rigidly affixed to arm 248 whichalso pivots about the point where shaft 246 connects Shaft 246 ispivotally mounted in bracket 250 affixed to platform 31.

To the upper end of lever 248 is pivotally connected the link 252 andthe other end of link 252 is pivotally connected to the central supportI5 of the trainer fuselage which is located below the universal jointI2. It will be appreciated there-, fore that whenever the trainer isbanked laterally in either direction, link 252 will cause arm 248 topivot in one direction or the other, the extent of such, rotationdepending upon the deree of the bank. This movement of lever 248 willcause shaft 246 to rotate in one direction or the other and the rotationof this shaft will cause the upper end of arm 242 to move toward oneside of the trainer fuselage or the other and therefore link I44 willlikewise reciprocate, moving extension I42 and causing leaf I30 torotate upon hollow shaft I46. The rotation of leaf I30 will movevacuum-filled counterbore I34 out of perfect engagement with port I60 ofleaf I52, and atmospheric ports I36 and I38 will be moved out of exactengagement with ports I62 and I64 respectively of leaf I52. Therefore,less vacuum will be applied to port I60 and less atmosphere will beapplied to ports I62 and I64 and less vacuum and less atmosphere will beapplied to the ports I68 and I10 if the throttles of the trainer be insuch a position that the leaf I66 is moved from its neutral position.The turning of the trainer in response to the uneven throttle positionsis therefore diminished. It is to be noticed, however, that thiscorrective banking of the trainer does not lessen the banking of theplane caused by uneven engine speeds, thereby simulating the case inactual flight where the Wing on the side of the slower engine tends tofall because of the lesser lift upon that wing as a result of the slowerengine speed. However, this wing may be raised by a movement of thecontrol column in the plane toward the higher wing, and the same is truein the trainer as shown in the same aforementioned U. S. patents.

In illustration, let us assume that throttle 56 is opened to agreaterextent than throttle 54, that is, it is moved farther to the leftin Fig. 2 than throttle 54. Link 69 willbe forced downwardly to agreater extent than link 68 and, therefore, port I10'of leaf I66 willcommunicate to an increased extent with port I160 of leaf I52 while portI68 of the former leaf will be placed in communication with port I 62 ofthe latter leaf. Vacuum will be. applied in greater magnitude throughconnection I14 to bellows 118 while atmosphere willbe applied throughconnection I12 to bellows I16. The former bellows will contract and thelatter will expand and rudder valve link I will be moved to the rear andthe trainer will be made to turn to the left. Now assuming that thetrainer be banked to the right, by means of link 252, arm 248, shaft246, arm 242, link I44 and extension I42, leaf I36 will be made torotate clockwise'upon hollow shaft I46 and vacuumfilled counterbore I34will become out of perfect engagement with port I 60, less vacuum willbe applied to port I60 of leaf I52 and, therefore, less vacuum will beapplied to port I 10 of leaf I166. Likewise, a reduction in the amountof vacuum applied to bellows "6 will result and air entering bleed holeI15 will cause that bellows to expand. At the same time, less atmospherewill fingth ent in connection 112 and lessjatm-os'phere will enterbellows I16" which" beilowstherecfore will bemadeto contract; 'The'expansion of bellows H8 and the contraction of bellows; H6 will offsetthemovement applied to rudder bar 186 asa result of the unequalthrottle'settings', and-the rate of turning of; the trainer will bedecreased. The

turning of the trainer to the, left, caused by an opening of throttle'56 to a greater extent than throttle 54- will therefore be, diminishedby the banking of the trainer' i-n the: direction opposite totheturning: If the trainer were turning to the right as'a result ofthrottle 514 being opened farther'thari throttle 55 a; ban-king of thetrainer to the left would; likewise diminish the turning soc'arused;

V V 20 It will: be seen that the turning of the trainer as agresuit ofsimulated uneven engines'peed'smay be dim-fnishedfhy a" banking of thetrainerin either direction. Of conrse'tl're-stndent mayccunter thisturning by applying; pressure to the rudder pedal'opposite the directionof the turning.

In addition to the-banking fthe plane and applying pressure to theopposite rudder, in"

planes -of the type being simulated additional means are usuallyprovided to overcome-the turn- .ing causedby unequal" engine speeds."These means are'generahyof twotypes', one means pro vid-ing'itsccrnpensation' through positioning the rudderpeda-ls and the otherthrough positioning I a tab' on therudder of the plane' Inasmuch as suchcompensating means in' the trainer "must means which have beenihcbrporated irr'my ineither type; v

same"resnitf"mey lite consid ered to be of I benefited to the ruddervalyejthe" following u h a te m te efw rmifi t ink m'w i' h' 1 ispitotaily attached towhenpper endv ofarm fij arist-rmov ql ay or h fihjer' ep n in uporr the direction of rctation of' the wheel 2"5'6". Theother vend'oi link 2% will move arm 262" chain ett in one directionortheiotner and the decreasedand at the same timeth'e tension upion jspr n 21H will be decreasedorincreased, :Inase i'eprihg- 26erc'onnectedtto 111m :v 212, the 1 a i (errdjot-whichis connecte djto theupper end: of rudder pedal lfit whiife the other end (if spring 27 9- isconne'eted to=link21lwhich has its other" end connected td the upperpart of 'rtid'der pedal l tyit will be realized that an increase in thetension upon spring fand'the simultaneous decrease the tension uponspringiz'm will cause the- ;ri-idcler gga'edal to move the same mannereugh the student in the trainer'were' applymg hislett foot 112:- leftrudder pefdal 268; while if womnfit betnrnecf insueh adirectionj thetension upon springiZFWis increased and that 1 upon spring 268decreesedf the rnddenpedals wilt respond as though the studentjnthe'trainer were actnal'ly a ppli'ifig his 7 right, foot; to rudderpeda1-i9$l--A- suitable-scale 2% end" an index rudder pedal: 1 or, W n:i qe of the. i we tar? t? con-trolmeans" t'eturn'anfd me -1am enme he tzes re provided so met;

' turning pt traineeeaaflsedgby the t r ieqdaf throttle settings.- p KMy'inventidnt ererere iovieesmea s wn rem: i thestude-nt inthe tmaineimaiylovercem the r ingef the tfiti'ner caused by assumed difierenes inengine speed's'in addition to appl'ying prfessflre to the-rudder pedals;and'harihing' the trainer- 7 In the event-that 'onef cth :b-elrqws'H5101 H3 be substantially eoritracted' throiaigh th a plicat'ion o'f'vacbyime "us of QQfiflt10jIJlF2 7 or IN, the na m1: respdnsef 6fthestiidentiin the trainer would bete appty his: foot to the' rfa'dderpedal: ant: sideei"the=contracted beilow In order te over emetne-atmcseric fdr ce being: exerted on onts'i de 0f the"- contracted hei lowss: Ithe: student would "be required to exert? are ordinat' ely iargei,eifhh'n ot farce. the": pedlk In order to overcome this dimc'ult theinks list;

and I185 are irire'ali'ty p'ositiveftype springeni zest 1's: attachedt6em 11m: rams Th-i's step' extend I and the" ends-of tilts stop proje heig-zso slotsi z'fi't vihich ar felts-th-sid '2 86. A- compression:spring 290' is; with 611 280; one end efthi-s -spririg bearing" a garis't-jtheinterior right I end or housing- 1 W and-thnther' endibeairing against thehe rizen 1 Spring. Z-Qflfhas a eempres'sion evereitherot the mums-11s: er FFBT by-an applih'a-tierf of --va;cnurhthereto -tlre sttfi v mve s'ubsta in slbt'sf i flt a therefererudderliar I86 5 I rods; $8 4" or were seed-gene n ei ther bellewsfleoryi'ffiFfbe e v v oftheredueed ai-r-f pressure therewithih; studentthe'ctrai er a plies; his -met-to th Will -cause a' e'o Frorn the foragestood-that mjfinve. s. cemplishingfthe stalted ahif'qthe inventibnf'Inasmuch as'nume ou changes; in preferred cdns'truetien may bemaev'ritfimt de parting from the spirit of my inye tion I Ii Qn'ybj-thefetltiv' 'giclaim myself 2. In an aeroplane,v trainer u v J V,bdntrfdl turning and 1 tiltine the cockpit the, on' t rew t :o tra t-ff moi lating throttle levers andig rhea other teactflateth controlmeans to" turn and g 21 tilt the cockpit, and an indicator simulatingthe air speed indicator of a real plane, and additional means operableby movement of the throttle levers either jointly or independently tocontrol the reading of said indicator.

3. In an aircraft pilot trainer, a pair of levers simulating motorcontrol levers, a diiferential device operable thereby to be moved inresponse to relative movement of said levers, and turning and bankingmeans operable by said difierential device.

4, In an aircraft pilot trainer, 9, pair of levers simulating thethrottle control levers of a dual engine plane, a diflerential deviceoperable thereby to be moved in response to relative movement of saidlevers, turning and banking means, operable by said differential device,and independent control means for restoring the normal position of thebanking and turning means independently of the relative position of saidlevers.

5. The combination of a grounded aviation trainer comprising a fuselage,means for rotating said fuselage in either direction about its verticalaxis, means for banking said fuselage laterally in simulation of thebanking of a plane in actual flight, a simulated vertical speedindicator in said fuselage, and means for actuating said indicator toindicate assumed vertical speeds, a plurality of simulated throttlecontrol levers in said trainer, and means operated by said simu latedthrottle control levers for causing said rotating means to rotate saidfuselage, said banking means to bank said fuselage and said actuatingmeans to cause said indicator to register in accordance with thecombined settings of said simulated throttle control levers.

6. The combination of a grounded aviation trainer comprising a fuselage,means for rotating said fuselage in either direction about its verticalaxis, means for banking said fuselage laterally in simulation of thebanking of a plane in actual flight, a simulated altimeter in saidfuselage, and means for actuating said simulated altimeter to indicateassumed altitudes, a plurality of simulated throttle control levers insaid trainer, and means operated by said simulated throttle controllevers for causing said rotating means to rotate said fuselage, saidbanking means to bank said fuselage and said actuatin means to causesaid simulated altimeter to register in accordance with the combinedsettings of said simulated throttle control levers.

7. In a grounded aviation trainer the combination of a fuselagerotatably mounted upon a universal joint, means for laterally bankingsaid fuselage in simulation of the banking of a plane in actual flightand means for rotating said fuselage about its vertical axis, aplurality of simulated throttle control levers within said fuselage,means for causing said rotating means to rotate said fuselage and saidbanking means to bank said fuselage according to the relative positionsof said simulated throttle control levers, and additional meansresponsive to the lateral banking position of said fuselage fordiminishing the rotation of said fuselage caused by the relativepositions of said simulated throttle control levers whenever saidfuselage is banked.

8. In a grounded aviation trainer the combination of a fuselagerotatably mounted upon a universal joint, means for laterally bankingsaid fuselage in simulation of the banking of a plane in actual flight,means for rotating said fuselage about its vertical axis, a plurality ofsimulated throttle control levers within said fuselage, and

I 22 a control element for controlling the rotation and banking of saidfuselage, said control element being responsive to the combinedpositions of said simulatedthrottle control levers and the lateralbanking position of said fuselage.

9. In an airplane trainer including a turnable cockpit, and controlmeans for turning the cockpit, the combination therewith of a pair oflevers simulating the throttle control levers of a dual engine plane,and means operable by movement of one of the levers with respect to theother to actuate the control means to turn the cockpit.

10. In an airplane trainer including a turnable cockpit, and controlmeans for turning the cockpit, the combination therewith of a pair oflevers simulating the throttle control levers of a dual engine plane,and means operable by movement of one of the levers with respect to theother to actuate the control means to turn the cockpit, an indicatorsimulating the air speed indicator of a real plane, and additional meansoperable by movement of the levers either jointly or independently tocontrol the reading of said indicator.

11. In an airplane trainer, a pair of levers simulating the throttlecontrol levers of a dual engine plane, a differential device operablethereby to be moved in response to relative movement of said levers andturning means operable by said differential device. I

12.In an airplane trainer including a turnable cockpit and control meansfor turning the cockpit, the combination therewith of a pair of leverssimulating the throttle control levers of a dual engine plane, meansoperable by movement of one of the levers with respect to the other-toactuate the control means to turn the cockpit, and independent controlmeans for restoring thenormal position of the control meansindependently of the relative position of said levers.

13. In an airplane trainer including a turnable cockpit and controlmeans for turning the cockpit, the combination therewith of a pair oflevers simulating the throttle control levers of a dual engine plane,and-means operable by movement of one of the levers with respect to theother to actuate the control means to turn the cockpit, a pair ofsimulated rudder pedals connected to said turning means for operatingsaid turning means, and additional simulated trimming means connected tosaid turning means, for operating said turning means.

14. In an airplane trainer the combination of a pair of leverssimulating the throttle control levers of a dual engine plane, asimulated air speed indicator, and means operable by movement of one ofthe levers with respect to the other to actuate said indicator.

15. In an airplane trainer including a turnable cockpit, and controlmeans for turning the cockpit, the combination therewith of a pair oflevers simulating multi-motor throttle control levers, and meansoperable by movement of one of the levers with respect to the other toactuate the control means to turn the cockpit.

16. In an aircraft pilot trainer including a turnable and tiltablecockpit, a pair of levers simulating the throttle control levers of adual engine plane, means operable by movement of one of the levers withrespect to the other to turn and tilt the cockpit, and independentcontrol means for restoring the normal position of the banking andturning means independently of the relative position of said levers;

17. In an aircraft pilot trainer, a pair of levers simulating motorcontrol levers, a device operg mme able ti i reb w bemweei respeese torem mev reemf-.ef-eeiaimvefi; meme e ser ame gine plane, and meanseperezbieey mevement df: 'one of the-levers with respot tothe other1263x561 I9 ain'- aeroplane traeiiier including a turn able cockpit, andoontroi'meams for tumirigthe' cockpit, the combinatioti' therewith of a:per-1 of leverssimulating the 'thnottIe-coritfiol levers se dual engineplane, means 0pe1 a b1eby movement of one of the Ieverswith respect theother to actuate the control means rto t'urrithe-eoe'lipit, "anindicator simulati'rig' the a'uir s'bee'dihd cater of a; real plane, andadditional means opera-Me by movemento'f; the throttle levei s eitherj'dintlyor v independently to control the residin -e1; saidin-vdieatolf. I

20'. Ari aircraft pilot traifier' comprising a, cock"- pit, meoha'nismoperaibIe to. cause the cockpit td turn, a manual control fihe eeekpwforpeiet lfi me frieans' operable by said device.

ing the said turn mechanism under contgot of the student, andadd'itionarmeme. separate from said manual control; for actuating meme-plianishi'to-Caiise the cockfiit-to turn in simulation of the action of atwin-meter aeroplane w'kiieh one-motor is delivering less-powerthanweather."

trainer, 251, si niii'lfeiina'dj eir speed ihdieetor the fe meansresponsive" tocertairr -contro1's'- traiiner for 'aictuavtiiig saidindicator to indicate;

assumed air speeds, phi-iafl i-ty of simulate-dthrottle eontrol leversihseid trainer, and mean 402-1 epemeeiey said @si'r n Iatecithrottie-oon trol leversfor -eusiz i gjlie said actuating means toramuse sasiefin'dieai rtoregfster in eeeofrderiee Wit he com-bifierfsefiti ngs of saiti simL i1 ated throttle co e-h .trol levers. r

I 2221i; m aircraft-pilot trainer, :3; 132511 03 fevers si motorco'utmlievers a; device operab'l'e erier iy tobe moved response to rel a'tivemovement; of said levers, and turning and lea-113k 23. In anraircraftpilot trainer, a pair of leveis siiffuhti-ifi Q-the thi' otfi-cofltr'oi-levers ofia dnfal eng e lane,- adeifi e} operae'-'- there-byt me'v'ee in response to rel a-tive movemefit of said ;,,1evers, teemingand banking means epembieby said? device; and i fr-d'epen'denteofitro'1-mea1 1sf;o1 the rioima-P'positioh ef the turning emig"meansindependently of the relative -po 24, An aircraft puee t'rainercompri'sing a2-C'0k"' pit; mechanisms operrble-to eause the coekpittotm'ir eindj batik; manua'P-controls' in the cockpitforfo'p'erait'iflgsaid turn and mechanisms-re specti jvew imder"co'niiroi of th'e student, aridi a"d+- i'diti-onec'i means sepaii'a te-f'ro nseid*m=a;nua1 cor i-- tr o for actuating saidmeehanisms to oausethe-- cockpit to" turn an-d bank in; simulation of the" one motor isdelivering less power than the other.

a simulated vertical. speed indicator is also prey 26. The structure setforth in m 14 in which a simulated altimeter is alsoiprovided andisoperated" by v the means operame by; movement of en e f thereversi withrespect to the: other;

' V ARL-LA;

The s'triietureset forth-in claim 141 inwhic'h-

